Method and apparatus for use in monitoring a physiological characteristic of a subject

Abstract

There is provided a method for use in monitoring a physiological characteristic of a subject, the method comprising: obtaining a general variability measure of the physiological characteristic, wherein the general variability measure is based on a historical data set of values of the physiological characteristic from a plurality of further subjects; calculating a personalization factor specific to the subject, based on physiological data relating to the subject; generating at least one personalized abnormality criterion for the physiological characteristic, based on the obtained general variability measure and the calculated personalization factor; receiving a measured value of the physiological characteristic of the subject; and determining whether the received measured value is abnormal by comparing it to the at least one personalized abnormality criterion, wherein the received measured value is determined to be abnormal if it meets the at least one personalized abnormality criterion.

1 . A method for use in monitoring a physiological characteristic of a subject, the method comprising:
 obtaining a general variability measure of the physiological characteristic, wherein the general variability measure is based on a historical data set of values of the physiological characteristic from a plurality of further subjects;   calculating a personalization factor specific to the subject, based on physiological data relating to the subject, wherein the physiological data relating to the subject comprises one or more of a determination of the right ventricular ejection fraction, RVEF, and/or the left ventricular ejection fraction, LVEF, the subject; a determined fitness level of the subject; and health conditions experienced by the subject;   generating at least one personalized abnormality criterion for the physiological characteristic based on the obtained general variability measure and the calculated personalization factor;   receiving a measured value of the physiological characteristic of the subject; and   determining whether the received measured value is abnormal by comparing it to the at least one personalized abnormality criterion, wherein the received measured value is determined to be abnormal if it meets the at least one personalized abnormality criterion.   
     
     
         2 . A method as claimed in  claim 1 , wherein the at least one personalized abnormality criterion comprises one or more of:
 a personalized maximum value of the physiological characteristic, such that a received measured value which is above the maximum value is determined to be abnormal; and   a personalized minimum value of the physiological characteristic, such that a received measured value which is below the minimum value is determined to be abnormal.   
     
     
         3 . A method as claimed in  claim 1 , wherein the at least one personalized abnormality criterion comprises a personalized range of normal values of the physiological characteristic, such that a received measured value which is outside the range of normal values is determined to be abnormal. 
     
     
         4 . A method as claimed in  claim 1 , wherein generating the at least one personalized abnormality criterion comprises determining a baseline value of the physiological characteristic, and wherein the at least one personalized abnormality criterion is generated based on the determined base line value, the obtained general variability measure, and the calculated personalization factor. 
     
     
         5 . A method as claimed in  claim 4 , wherein the baseline value is a personalized baseline value, which is determined using data specific to the subject. 
     
     
         6 . A method as claimed in any preceding claim, wherein generating the at least one personalized abnormality criterion comprises:
 defining at least one general abnormality criterion based on the obtained general variability measure; and   adjusting the at least one general abnormality criterion based on the personalization factor.   
     
     
         7 . A method as claimed in  claim 1 , wherein generating the at least one personalized abnormality criterion comprises:
 calculating a personalized variability measure based on the general variability measure and the personalization factor; and   defining at least one personalized abnormality criterion based on the personalized variability measure.   
     
     
         8 . A method as claimed in  claim 1 , comprising receiving at least one further measured value having an earlier measurement time than the received measured value, and wherein determining whether the received measured value is abnormal comprises assessing whether the at least one further measured value meets the at least one abnormality criterion, and determining the received measured value to be abnormal if both of the at least one further measured value and the received measured value meet the at least one abnormality criterion. 
     
     
         9 . A method as claimed in  claim 1 , wherein the general variability measure comprises the standard deviation of the historical data set. 
     
     
         10 . A method as claimed in  claim 1 , wherein the personalization factor comprises a scaling factor. 
     
     
         11 . (canceled) 
     
     
         12 . A method as claimed in  claim 1 , wherein calculating the personalization factor comprises:
 comparing the physiological data relating to the subject to a data base correlating physiological data of the same type as the physiological data relating to the subject with variability of the physiological characteristic, to determine a subject-specific variability associated with the physiological data relating to the subject; and   comparing the subject-specific variability with the general variability measure.   
     
     
         13 . A computer program product, comprising computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor, the computer or processor performs the method described in  claim 1 .. 
     
     
         14 . An apparatus for use in monitoring a physiological characteristic of a subject, the apparatus comprising:
 a processing unit arranged to:   obtain a general variability measure of the physiological characteristic, wherein the general variability measure is based on a historical data set of values of the physiological characteristic from a plurality of further subjects;   calculate a personalization factor specific to the first subject, based on physiological data relating to the first subject, wherein the physiological data relating to the subject comprises one or more of a determination of the right ventricular ejection fraction, RVEF, and/or the left ventricular ejection fraction, LVEF, of the subject; a determined fitness level of the subject; and health conditions experienced by the subject;   generate at least one personalized abnormality criterion for the physiological characteristic, based on the obtained general variability measure and the calculated personalization factor, wherein a given received measured value is determined to be abnormal if it meets the at least one personalized abnormality criterion;   receive a measured value of the physiological characteristic of the subject; and   determine whether the received measured value is abnormal by comparing it to the at least one personalized abnormality criterion.   
     
     
         15 . A system for use in monitoring a physiological characteristic of a subject, the system comprising:
 a measurement device for measuring a physiological characteristic of a subject, wherein the measurement device is arranged to output a measured value of the physiological characteristic; and   an apparatus according to  claim 13 , wherein the processing unit is arranged to receive a measured value output by the measurement device.